Problem: What is the least common multiple of 10 and 15? Another way to say this is: $\lcm(10, 15) = {?}$
Solution: The least common multiple is the smallest number that is a multiple of 10 and 15. We know that 10 x 15 (or 150) is a common multiple, but is it the least common multiple? Write out the multiples of 15 until we find a number divisible by 10. 15, 30, So, 30 is the least common multiple of 10 and 15.